Ventriculoperitoneal Shunt Complications In Children: An Evidence-Based Approach To Emergency Department Management

Table of Contents

 

1. Abstract
2. Case Presentations
3. Introduction
4. Critical Appraisal of the Literature
5. Pathophysiology
6. Differential Diagnosis
7. Prehospital Care
8. Emergency Department Evaluation
   1. Focused History
      1. Signs And Symptoms
         • Clinical Signs And Symptoms
         • Seizure
         • Myelodysplasia
      2. Summary
   2. Physical Examination
   3. Pumping The Shunt
9. Diagnostic Studies
   1. Imaging
10. Treatment
11. Special Circumstances/Populations
    1. No Neurosurgeon In-House
    2. Ventriculoatrial And Ventriculopleural Shunts
12. Controversies And Cutting Edge
13. Disposition
14. Summary
15. Risk Management Pitfalls For Patients With VP Shunt Complications
16. Time- And Cost-Effective Strategies
17. Case Conclusions
18. Clinical Pathway For The Management Of Suspected VP Shunt Malfunctions
19. Clinical Pathway For The Management Of Suspected VP Shunt Infections
20. Tables and Figures
    1. Table 1. Shunt Complications
    2. Table 2. Key Questions For Patients With A Ventriculoperitoneal Shunt Who Present With Acute Illness
    3. Table 3. Signs And Symptoms Of Shunt Complications, Acute Versus Subacute & Chronic
    4. Table 4. Clinical Predictors Of Shunt Complications
    5. Table 5. Emergency Department Evaluation Of Shunt Complications
    6. Table 6. Management Of Specific Shunt Complications
    7. Figure 1. Hydrocephalus, Dilated Ventricles Seen On Head Computed Tomography
    8. Figure 2. Shunt Components Of Ventriculoperitoneal And Ventriculoatrial Shunts
    9. Figure 3. Slit-Like Ventricles On A Head Computed Tomography Scan
    10. Figure 4. Cerebrospinal Fluid Pseudocyst On A Computed Tomography Scan
    11. Figure 5. Radiographic Images From A Shunt Series
    12. Figure 6. Fracture Of A Ventriculoperitoneal Shunt
21. References

Abstract

Although much is known about ventriculoperitoneal shunts, there are still large gaps in the literature and no evidence-based guidelines on management. To date, there is no general consensus on workup and treatment, and there are many differing diagnostic and therapeutic strategies for management of complications. Ventriculoperitoneal shunt complications can be separated into 3 categories: mechanical failure, infection, and functional failure. Knowing the basic anatomy of ventriculoperitoneal shunts, the time of shunt placement, and the clinical manifestations suggestive of potential complications can help with the management of patients with ventriculoperitoneal shunts. This review summarizes the literature on complications of ventriculoperitoneal shunts, examines the literature regarding the workup and management of patients with ventriculoperitoneal shunts, and makes recommendations for the management of these patients in the emergency department.

Case Presentations

A 7-year-old girl with a history of a VP shunt presents with a headache for 2 days and worsening fever. The patient’s mother states that the child had a shunt placed during her first year of life for congenital aqueductal stenosis. The patient is febrile in the ED, with a temperature of 38.6°C, but is nontoxic. Her other vital signs are: heart rate, 118 beats/min; respiratory rate, 20 breaths/min; blood pressure 98/62 mm Hg; and oxygen saturation, 100% on room air. Her physical examination is unremarkable except for a mildly erythematous throat. What are important points on your history that should be elicited for a patient with a VP shunt and fever? If you are concerned about a VP shunt infection, what laboratory studies should be ordered? Do you need to order any imaging studies to look for a possible shunt malfunction? Should you call this child’s neurosurgeon?

A 3-year-old girl with a VP shunt, who is suffering from altered consciousness and persistent vomiting, is brought to your community ED via EMS. The patient’s mother states the child has been drowsy for the past few weeks. Upon arrival, you place the girl on a monitor and a nonrebreather mask and obtain the following vital signs: heart rate, 76 beats/min; respiratory rate, 20 breaths/min; blood pressure, 110/65 mm Hg; and oxygen saturation, 100% on the nonrebreather. Upon primary survey, the patient’s airway is intact, but there are coarse breath sounds bilaterally over her chest. Her capillary refill is < 2 seconds. Her GCS score is 9, and you note that one pupil seems to be more dilated than the other and appears to be sluggishly reactive. The patient is not responding to your commands. What could be causing this patient’s symptoms? Without a neurosurgeon in-house, what should your management of this patient be? Does the patient need imaging prior to any procedures?

A 5-year-old boy with a history of constipation, mild developmental delay, and a VP shunt presents with 1 week of vomiting. His mother states he is chronically on stool softeners. For the past week, the patient has had 2 to 3 episodes of nonbloody, nonbilious vomiting per day. He has not had diarrhea, but his last stool, which was earlier today, was watery. The mother states he has not been complaining of headaches, but has been eating and drinking less. His vital signs are stable upon arrival. The patient’s examination is normal, including the neurologic examination, except for mild periumbilical tenderness. There is no rebound or guarding upon abdominal palpation. You realize that this could be a typical presentation of constipation, but the patient’s VP shunt makes you consider possible shunt complications. You begin to wonder if this could possibly be a shunt obstruction or infection. What steps should be taken in the management of this patient? What history is important in this case? What physical examination findings might help with the diagnosis?

Introduction

Ventriculoperitoneal (VP) shunts are the treatment of choice for patients with hydrocephalus, an excessive accumulation of cerebrospinal fluid (CSF) within the brain caused by an imbalance between CSF production, flow, or absorption. Most commonly, pressure builds up proximal to an obstruction, leading to ventricular dilatation and raised intracranial pressure (ICP).¹ (See Figure 1). The pathophysiology of hydrocephalus has been known since the 1800s, but effective treatment was not available until the 1950s, when John Holter developed a shunt to allow drainage of excess CSF, in an attempt to treat his own son, who was suffering from hydrocephalus.² Since then, the standard treatment of hydrocephalus has been the insertion of a ventricular shunt, and it has dramatically reduced the morbidity and mortality of hydrocephalus.^3,4

A shunt consists of 4 major components: a proximal catheter, a 1-way valve, a reservoir, and a distal catheter.⁵ (See Figure 2.) Most neurosurgeons place shunts that contain medium-pressure valves and drain CSF continuously when the pressure in the ventricles is > 10 mm Hg.⁶ The proximal catheter is normally inserted in the parieto-occipital region of the lateral ventricle, and the 1-way valve and reservoir run behind the ipsilateral ear. The distal portion of the catheter is tunneled down through the neck and chest wall and, most commonly, ends in the peritoneal cavity.^3,5 Other areas where the catheter can terminate include the pleural cavity, atrium, and gallbladder; however, the peritoneal cavity is the preferred site of termination, as it is associated with the fewest complications.⁷ If placed in infancy or childhood, the distal catheter has extra length in the abdomen to allow for growth of the patient. Many newer valves allow for the opening pressure to be adjusted externally via a magnetic or electromagnetic device; these “programmable" shunts obviate the need for surgery to change the pressure setting.¹

Unfortunately, VP shunts are not long-lasting, and revision may be required 1 to 2 times every 10 years.³ The Pediatric Shunt Design Trial was a randomized controlled trial that compared differ-ent types of shunts in patients with hydrocephalus. According to this prospective study, approximately one-third of shunts require revision in the first postoperative year and > 50% fail by the second year after insertion.⁸ This study, as well as others, found failure to be independent of valve type.^1,7,8 There are several risk factors for complications, including: younger age, history of prematurity, number of revisions, and shorter time from insertion to first revision.^4,9-11 Ethnicity also has been linked to shunt complications. Specifically, blacks, Hispanics, and Native Americans have a higher rate of complications compared to Asians and whites.^4,12,13 The number of shunt placements is increasing each year. The annual malfunction rate is projected to be as high as 5%.^5,14 The mortality rate from a shunt malfunction can be as high as 1% to 2%.¹⁵

Both the history and physical examination are very important when evaluating a patient with a possible shunt complication, and will guide the emergency clinician in making management decisions. This issue will help practitioners identify possible shunt complications, determine necessary diagnostic and management steps, and decide appropriate dispositions.

Critical Appraisal Of The Literature

Risk Management Pitfalls For Patients With VP Shunt Complications

1. “I am concerned that my patient may have a VP shunt obstruction. The neurosurgical resident is at the bedside and pumps the shunt, which has free flow. Because of this, he wants to send the patient home.”
   Pumping the shunt has been shown not to be a reliable predictor of shunt patency. If clinical suspicion for an obstruction is still high, further workup and management may be needed.
2. “My patient has clinical signs of shunt obstruction, but has a normal head CT scan and shunt series, so his symptoms must not be related to his shunt.”
   Unfortunately, many patients can have normal or unchanged imaging and still have a shunt complication. If the suspicion for a shunt complication is high, it is advisable to discuss the case with the patient’s neurosurgeon and consider further imaging or intervention.
3. “My patient has large ventricles on a head CT scan, so there must be a shunt malfunction.”
   Comparing the studies with previous imaging should always be done, whenever possible, to determine whether there is any change in the ventricle size. Also, the clinical picture should be taken into consideration.
4. “My patient is presenting with signs of a possible shunt complication. The head CT scan is normal, and, therefore, a shunt series is not necessary.”
   Although rare, there are cases of a normal head CT scan with an abnormal shunt series. Therefore, a shunt series should be obtained.
5. “Every patient with a VP shunt and fever needs laboratory work and diagnostic studies.”
   The clinical picture needs to be considered for each patient. A focused history and physical examination should be obtained and key features of shunt infection should be focused upon, such as bulging fontanel, drowsiness, lethargy, or erythema around the shunt. Laboratory values are not specific. Not all shunt infections need imaging—if a shunt infection is suspected, a shunt tap is needed.
6. “My patient with a VP shunt appears ill, but there is no history of fever. Therefore, a shunt infection can be excluded.”
   A patient can have a shunt infection without fever. Other signs and symptoms may be present that can suggest a possible shunt infection. A full history and physical examination should be obtained.
7. “My patient with a VP shunt presents with abdominal pain and vomiting; this cannot be related to the shunt.”
   Abdominal pain and vomiting in a patient with a VP shunt can be a sign of shunt malfunction, or due to common viral or other illnesses. For example, patients with constipation and a pseudocyst can present similarly. Again, a detailed history and physical examination are needed, as well as potential imaging.
8. “Although my patient is stable, I am concerned about a possible shunt infection, so I will perform a shunt tap.”
   This is an option, if this has been discussed with the neurosurgeon and you feel comfortable performing a tap. Typically, however, a shunt tap is performed by an emergency physician only emergently when a patient is acutely decompensating. There are many risks associated with shunt taps, and this procedure should be performed by a neurosurgeon, if possible.
9. “My patient with a VP shunt has clinical signs of increased ICP with impending herniation, but I want to wait for neurosurgery to perform a shunt tap.”
   As stated in pitfall 8, this is the only circumstance when an emergency physician is truly obligated to perform a shunt tap, as it is a potentially life-saving intervention.
10. “My patient with a history of seizures and a VP shunt presented with a breakthrough seizure; this must be a shunt malfunction or infection.”
    Seizures alone are not necessarily a clinical manifestation of a shunt infection or malfunction. The more concerning signs and symptoms the patient has, the higher the likelihood of a VP shunt malfunction or infection.

Tables and Figures

References

Evidence-based medicine requires a critical appraisal of the literature based upon study methodology and number of subjects. Not all references are equally robust. The findings of a large, prospective, randomized, and blinded trial should carry more weight than a case report.

To help the reader judge the strength of each reference, pertinent information about the study, such as the type of study and the number of patients in the study are included in bold type following the references, where available. The most informative references cited in this paper, as determined by the authors, are noted by an asterisk (*) next to the number of the reference.

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